Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B1/00—Layered products having a non-planar shape
  • B32B1/08—Tubular products
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
  • B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
  • B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
  • B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/30—Extrusion nozzles or dies
  • B29C48/305—Extrusion nozzles or dies having a wide opening, e.g. for forming sheets
  • B29C48/307—Extrusion nozzles or dies having a wide opening, e.g. for forming sheets specially adapted for bringing together components, e.g. melts within the die
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/30—Extrusion nozzles or dies
  • B29C48/32—Extrusion nozzles or dies with annular openings, e.g. for forming tubular articles
  • B29C48/335—Multiple annular extrusion nozzles in coaxial arrangement, e.g. for making multi-layered tubular articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/49—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using two or more extruders to feed one die or nozzle
  • B29C48/495—Feedblocks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/92—Measuring, controlling or regulating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L11/00—Hoses, i.e. flexible pipes
  • F16L11/04—Hoses, i.e. flexible pipes made of rubber or flexible plastics
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L9/00—Rigid pipes
  • F16L9/12—Rigid pipes of plastics with or without reinforcement
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92009—Measured parameter
  • B29C2948/92114—Dimensions
  • B29C2948/92152—Thickness
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92504—Controlled parameter
  • B29C2948/92609—Dimensions
  • B29C2948/92647—Thickness
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92504—Controlled parameter
  • B29C2948/92704—Temperature
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92819—Location or phase of control
  • B29C2948/92857—Extrusion unit
  • B29C2948/92876—Feeding, melting, plasticising or pumping zones, e.g. the melt itself
  • B29C2948/92895—Barrel or housing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92819—Location or phase of control
  • B29C2948/92857—Extrusion unit
  • B29C2948/92904—Die; Nozzle zone
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92819—Location or phase of control
  • B29C2948/92942—Moulded article
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/07—Flat, e.g. panels
  • B29C48/08—Flat, e.g. panels flexible, e.g. films
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2027/00—Use of polyvinylhalogenides or derivatives thereof as moulding material
  • B29K2027/12—Use of polyvinylhalogenides or derivatives thereof as moulding material containing fluorine
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2327/00—Polyvinylhalogenides
  • B32B2327/12—Polyvinylhalogenides containing fluorine
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2377/00—Polyamides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
  • B32B37/14—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers
  • B32B37/15—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state
  • B32B37/153—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state at least one layer is extruded and immediately laminated while in semi-molten state

Definitions

• the present invention relates to a production method of multilayer laminates which comprises laminating a polyamide and a fluorine-containing ethylenic polymer by simultaneous multilayer coextrusion.
• Multilayer laminates formed by laminating a polyamide and a fluorine-containing resin are expected as composite materials having polyamide characteristics, such as high strength, high toughness, light weight, good processability and in particular, flexibility, as well as fluorine-containing resin characteristics, such as heat resistance, oil and chemical resistance, and low liquid agent permeability.
• the successive lamination method and simultaneous lamination method are known for producing such multilayer laminates.
• the simultaneous lamination method, especially coextrusion method holds an important position because of its merit lying in that the number of steps required for obtaining the laminate can be lowered.
• the simultaneous multilayer coextrusion method is applied to multilayer molding or multilayer film formation using two or more extruders and, currently, films, sheets, extruded molded articles called profiles, pipes, hoses, tubes and other moldings varied in shape or form are being produced by the method.
• the method is applicable to various thermoplastic resins, such as polyamides, as well as to fluorine-containing resins.
• fluorine-containing resins are characterized in that they are low in intermolecular cohesive force and very low in surface free energy because of the low polarizability of fluorine-containing molecules. Therefore, they can hardly be wet against solids higher in intermolecular cohesive force, hence they show low adhesive properties against most of other substances. They, as resins, are thus characteristically poor in adhesion properties and their interlayer adhesiveness with polyamides is low; it is therefore necessary to contrive to increase the interlayer adhesion strength.
• methods are known which comprise subjecting the surface of the fluorine-containing resin to surface treatment such as corona discharge treatment or irradiation treatment.
• Japanese Kokai Publication Hei-05-8353 proposes a method of producing multilayer tubes comprising a polyamide resin as an outer layer and a fluorine-containing resin as an inner layer by irradiating the tubes to introduce intermolecular crosslinking structures among molecules in both layers and thereby secure the adhesion strength between the polyamide resin layer and the fluorine-containing resin layer.
• the method cannot be applied to the simultaneous lamination technique including coextrusion.
• Japanese Kokai Publication Hei-07-53823 discloses a method of producing multilayer tubes comprising an outer layer comprising a polyamide and an inner layer comprising a fluorine-containing resin in which a resin composition comprising both a specific polyamide and a fluorine-containing resin is laminated to a polyamide layer so that it may serve as an adhesive layer with the inner layer.
• the morphology of the adhesive layer changes according to the molding conditions due to the intrinsically poor compatibility between the constituent resins of the adhesive layer, namely the polyamide and fluorine-containing resin, and the morphology change influences on the cohesive force of the adhesive layer itself and the adhesion strength thereof with the other layers.
• problems arise as a tendency toward variation in adhesion strength according to environmental factors such as molding conditions and temperature conditions during use and difficulty in securing a constant quality level.
• this technology does not intend to increase the adhesiveness of the polyamide and fluorine-containing resin themselves but merely utilizing the adhesiveness of the polymer blend.
• the use of such polymer blend in lieu of the fluorine-containing resin results in an impairment in those excellent characteristics of the fluorine-containing resin.
• WO 99/45044 pamphlet there is disclosed a method of multilayer simultaneous extrusion of laminates which comprises polyamide 12 (nylon 12) as an outer layer and a fluorine-containing ethylenic polymer having carbonyl groups, such as carbonate groups and/or carbonyl halide groups, as an inner layer fluorine-containing resin to be laminated to the outer layer.
• the die temperature is set at 260°C, and an interlayer adhesion strength of ten and several of N/cm and a good appearance can be obtained.
• such a level of adhesion strength is not fully sufficient in some fields of application.
• the die temperature in extrusion molding of nylon 11 or nylon 12 as so far employed is within the range of 240 to 250°C and, even in lamination with a fluorine-containing resin, a temperature range exceeding 260°C has never been employed as the die temperature in molding nylon 11 or nylon 12, as described in the above-cited WO 99/45044 pamphlet.
• the present inventors unexpectedly found that when a die temperature in a specific range exceeding the temperature range conventionally employed is used for lamination by simultaneous multilayer coextrusion, the above object can be accomplished and, based on this finding, they have now completed the present invention.
• the present invention relates to a production method of a multilayer laminate which comprises laminating at least a polyamide (A) and a fluorine-containing ethylenic polymer (B) by simultaneous multilayer coextrusion using a coextrusion apparatus to obtain the laminate comprising said polyamide (A) and said fluorine-containing ethylenic polymer (B), said coextrusion apparatus comprising a die and a plurality of extruders for feeding resins to the die, and the temperature of said die being set within the range exceeding 260°C, preferably not lower than 265°C, more preferably not lower than 270°C, but not higher than 310°C, preferably not higher than 300°C, more preferably not higher than 290°C.
• the temperature of a feed block in case that the feed block is connected to the die, is also set within the range, namely above 260°C but not higher than 310°C.
• a cylinder temperature of the extruder for feeding the polyamide (A) to said die is set at a level higher by 20 to 90°C than the melting point of the polyamide (A), or the temperature of the polyamide (A) at a resin inlet, connected to the extruder, of the die, or of the feed block, in case that the feed block is connected to the die, is set at a level higher by 20 to 90°C than the melting point of the polyamide (A).
• the above polyamide (A) is nylon 11 or nylon 12.
• the fluorine-containing ethylenic polymer (B) is a fluorine-containing ethylenic polymer having carbonyl group with a carbonyl group content of 3 to 1,000 groups, in total, per 1 ⁇ 10 6 main chain carbon atoms.
• the simultaneous multilayer coextrusion is carried out by a technique selected from the group consisting of a multilayer film coextrusion, multilayer sheet coextrusion, multilayer blow coextrusion, multilayer profile coextrusion, multilayer pipe coextrusion, multilayer tube coextrusion, multilayer wire coating coextrusion and multilayer steel pipe coating coextrusion techniques.
• the above simultaneous multilayer coextrusion technique is carried out by a technique selected from the group consisting of a lamination technique in front of the die, a lamination technique within the die and a lamination technique behind the die, in which resins to be coextruded are joined for multilayer formation in front of the die, within the die and behind the die, respectively.
• the above die may be a flat die or a circular die, preferably a circular die in which resin spreading is effected by a type selected from the group consisting of spider, crosshead and spiral types.
• the present invention also relates to an automotive fuel piping tube or hose each having an at least three-layer structure comprising, as an outer layer, a layer comprising a polyamide (A); as an intermediate layer, a layer comprising a fluorine-containing ethylenic polymer (B); and, as an inner layer, a layer (C) comprising a fluorine-containing resin and containing or not containing an electrically conductive material, said fluorine-containing resin having a melting point not lower than 250°C.
• the present invention further relates to an automotive fuel piping tube or hose each having an at least four-layer structure comprising, as an outer layer, a layer comprising a polyamide (A); as an intermediate layer, a layer comprising a fluorine-containing ethylenic polymer (B); a layer (C) comprising a fluorine-containing resin and not containing an electrically conductive material; and, as an innermost layer, a layer (D) comprising a fluorine-containing resin and containing an electrically conductive material, wherein at least one of the fluorine-containing resin of the layer (C) and the fluorine-containing resin of the layer (D) has a melting point not lower than 250°C.
• a coextrusion apparatus comprising a die and a plurality of extruders respectively feeding, to the die, at least a polyamide (A) and a fluorine-containing ethylenic polymer (B), where necessary together with another resin or other resins is used.
• this apparatus is first described in detail.
• the above-mentioned simultaneous multilayer coextrusion is carried out using a coextrusion apparatus having a constitution comprising a die and a plurality of extruders feeding resins mentioned above to the die.
• the coextrusion apparatus may have a constitution comprising a plurality of extruders to be described below in detail which feed the above-mentioned raw material resins to the die, the die, a cooling apparatus for cooling and shaping (sizing) the resins that have passed through the die(s), a treatment system disposed when necessary for corona treatment, flame treatment, ozone treatment and/or the like, and a take-up unit of a molded article.
• the plurality of extruders is generally disposed for feeding the raw material resins for forming the respective layers, and the number thereof is equal to the number of the constituent layers. However, it is not always necessary for the number of extruders to be equal to the number of the constituent layers. Any known constitution capable of feeding the specified resins to each die can be employed.
• the fundamental structure of the extruder is not particularly restricted but preferably is of the screw type.
• the screw extruder generally comprises an adapter (connecting part between the extruder and die), screw, cylinder, hopper, and cylinder temperature control unit.
• the above screw extruder may be a single-screw extruder or a twin-screw extruder.
• a single-screw extruder is used.
• the extruder may be provided with a vent hole so that the volatile substances generated from the resin may be excluded upon opening the vent hole or reducing the pressure through it.
• the respective raw material resins sufficiently melted in the extruders are then fed to a die, or to the so-called feed block when such block is connected to the die for joining resins to be coextruded for multilayer formation in front of the die. Therefore, the raw material resins are fed to the die from the extruders via the adapter, or via the feed block from the adaptor when the feed block is connected to the die.
• the resins may also be fed from the extruder to the die or feed block via a gear pump in order to maintain the extrusion output at a constant level and thereby control the thickness of molded articles more precisely.
• the die may appropriately be selected according to the application use.
• a flat die or a circular die for inflation films
• a pipe or tube die circular die
• a blow die in multilayer blow molding a profile die in multilayer profile molding
• a wire coating die in molding multilayer wire coatings or a pipe coating die in molding multilayer steel pipe coatings.
• the resin is spread in the flow channel within the die.
• the manner of spreading may be, for example, by the spider method, by the cross head method enabling extrusion in a direction 90° to the extruder, or by the spiral method.
• the spiral method is preferred since a uniform layer thickness can be obtained thereby.
• the length of the flat portion of a die mandrel of the circular die can appropriately be selected and may be about 50 to 200 mm, for instance.
• the position of joining the resin layers fed from the respective extruders for multilayer formation is preferably within the die but may be any or a combination of the modes mentioned below.
• the temperature of the above die is set at a level within the range of above 260°C, preferably not lower than 265°C, more preferably not lower than 270°C, but not higher than 310°C, preferably not higher than 300°C, more preferably not higher than 290°C. Therefore, it may appropriately be set at 265 to 300°C, more preferably 270 to 290°C.
• a die temperature below 260°C it is impossible to obtain sufficiently high interlayer adhesion strength and, at above 310°C, the resins undergo marked thermal degradation and the multilayer laminates obtained thus show decreased strength and elongation and a poor appearance.
• the temperature is limited within the above range.
• the die temperature but also the temperature of the feed block be set at a level within the range of above 260°C, preferably not lower than 265°C, more preferably not lower than 270°C, but not higher than 310°C, preferably not higher than 300°C, more preferably not higher than 290°C. In this case, it is preferred that the die and feed block should be at the same temperature.
• the cylinder temperature of the extruder for feeding the polyamide (A) to the above die be higher by 20 to 90°C than the melting point of the polyamide (A) or that the temperature of the polyamide (A) at the resin inlet (adapter section), which is connected to the extruder, of the die (the above mode ii or iii) or of the feed block (the above mode i) in case that the feed block is connected to the die, be higher by 20 to 90°C than the melting point of the polyamide (A).
• the temperature in question is set at a level higher by 30 to 80°C than the melting point of the polyamide (A). In this case, the difference between the cylinder temperature and the above die temperature is relatively small, so that there is no possibility of its causing a marked increase in resin pressure in the die.
• the polyamide so referred to herein means a crystalline macromolecule having the amide bond -NH-CO- in a repeating unit within the molecule.
• nylon resins namely resins in which a majority of amide bonds are bound to an aliphatic or alicyclic structure.
• the polyamide to be used in the practice of the invention may have a structure having no amide bond in a repeating unit as partially occurring within the polyamide in a block or graft form.
• the polyamide elastomers such as nylon 6/polyester copolymers, nylon 6/polyether copolymers, nylon 12/polyester copolymers and nylon 12/polyether copolymers.
• These polyamide elastomers are block copolymers resulting from copolymerization of nylon resin oligomers and polyester resin oligomers or polyether resin oligomers by forming ester bonding or ether bonding.
• polyester resin oligomers include, for example, polycaprolactone and polyethylene adipate
• polyether resin oligomers include, for example, polyethylene glycol, polypropylene glycol and polytetramethylene glycol.
• Particularly preferred embodiments are nylon 6/polytetramethylene glycol copolymers and nylon 12/polytetramethylene glycol copolymers.
• the polyamide is preferably selected from among appropriate species having a melting point of not lower than 130°C, more preferably not lower than 150°C.
• the melting point is lower than 130°C, the layer formed therefrom may be poor in mechanical properties, heat resistance or the like.
• the polyamide preferably has a relative viscosity which indicates a molecular weight of not less than 1.8, more preferably not less than 2.0.
• the resin may show poor moldability, giving moldings inferior in mechanical properties.
• the upper limit is preferably not more than 4.0. If it exceeds 4.0, the polymerization of the resin itself is difficult and, even if the resin is obtained, the resin may be poor in moldability.
• the above-mentioned relative viscosity is determined as described in JIS K 6810.
• nylon 11 and nylon 12 are more preferred among others in view of the occurrence of zinc chloride water sprinkled over roads as a snow melting agent.
• the above polyamide may contain, in addition to the amide group, a functional group or groups selected from the group consisting of hydroxyl group, carboxyl group, ester group and sulfonamide group in a total amount of 0.05 to 80 equivalent percent relative to the amide group.
• a functional group or groups selected from the group consisting of hydroxyl group, carboxyl group, ester group and sulfonamide group in a total amount of 0.05 to 80 equivalent percent relative to the amide group.
• a sulfonamide group is preferred and it is particularly preferred that the polyamide contains a sulfonamide group or groups directly bound to an aromatic ring.
• the total content of the functional group(s) other than the amide group is preferably 1 to 70 equivalent percent, more preferably 1 to 50 equivalent percent, relative to the amide group.
• Such a polyamide as mentioned above may be one resulting from copolymerizing a copolymerizable monomer having such a functional group or groups with the polyamide-based resin in such an amount that the above-mentioned content of the functional group(s) can be attained, or incorporating a plasticizer having at least one functional group species selected from the group consisting of hydroxyl group, carboxyl group, ester group and sulfonamide group or a macromolecule having such a functional group(s) and compatible with the polyamide so that the above-mentioned functional group content may be attained.
• the above-mentioned macromolecule having such a functional group(s) and compatible with the polyamide includes, for example, ester- and/or carboxylic acid-modified olefinic resins (ethylene/methyl acrylate copolymers, ethylene/acrylate copolymers, ethylene/methyl acrylate/maleic anhydride copolymers, ethylene/ethyl acrylate copolymers, propylene/maleic anhydride copolymers, etc.), ionomer resins, polyester resins, phenoxy resins, ethylene-propylene-diene copolymers, and polyphenylene oxide.
• ester- and/or carboxylic acid-modified olefinic resins ethylene/methyl acrylate copolymers, ethylene/acrylate copolymers, ethylene/methyl acrylate/maleic anhydride copolymers, ethylene/ethyl acrylate copolymers, propylene/maleic anhydride copolymers, etc.
• the method comprising incorporating a plasticizer is advantageous in that not only the desired amount of the above-mentioned functional group(s) can be incorporated at a relatively low addition level but also the effects intrinsic in the plasticizer can be shown in rendering the resin composition flexible and improving the cold temperature mechanical properties of tubes or hoses, in particular.
• the addition level may vary depending on the plasticizer species.
• the above functional group content can be attained at an addition level of about 5 to 20% by weight relative to the whole amount of the composition.
• plasticizers there may be mentioned, for example, alcoholic hydroxyl group-containing compounds such as hexylene glycol and glycerol; phenolic hydroxyl group-containing compounds such as ⁇ -naphthol, dibenzylphenol, octylcresol, bisphenol A and like bisphenol compounds, octyl p-hydroxybenzoate, 2-ethylhexyl p-hydroxybenzoate and heptyl p-hydroxybenzoate; carboxyl group-containing compounds such as p-hydroxybenzoic acid-ethylene oxide and/or propylene oxide adducts; ester group-containing compounds such as octyl p-hydroxybenzoate, 2-ethylhexyl p-hydroxybenzoate, heptyl p-hydroxybenzoate and like benzoic acid esters and, further, ⁇ -caprolactone, phosphate esters of phenolic compounds, and the like; and sulfonamide
• the amine value of the polyamide in which the plasticizer is incorporated is not particularly restricted.
• the value is generally less than 10 equivalents/10 6 g, and such polyamides can be used.
• Polyamides having greater amine values, for example within the range of 10 to 60 equivalents/10 6 g, can also be used.
• the polyamide preferably has an acid value not higher than 80 equivalents/10 6 g.
• the polyamide may contain another resin, a colorant and/or one or more of various additives unless the object of the invention is deteriorated.
• additives there may be mentioned, for example, antistatic agents, flame retardants, heat stabilizers, ultraviolet absorbers, lubricants, mold-release agents, nucleating agents, and reinforcing agents (fillers).
• the fluorine-containing ethylenic polymer according to the invention may comprise a homopolymer chain or copolymer chain having the repeating unit derived from at least one fluorine-containing ethylenic monomer species, and the polymer chain may be one resulting from polymerization of a fluorine-containing ethylenic monomer or monomers alone or from polymerization of a fluorine-containing ethylenic monomer or monomers and a fluorine atom-free ethylenic monomer or monomers.
• the above-described fluorine atom-free ethylenic monomer is preferably selected from among ethylenic monomers containing not more than 5 carbon atoms so that the heat resistance, chemical resistance and like characteristics may not be reduced. Specifically, there may be mentioned ethylene, propylene, 1-butene, 2-butene, vinyl chloride, vinylidene chloride, etc.
• the monomer composition may have a ratio of 10 to 100 mole percent (e.g. 30 to 100 mole percent) of the fluorine-containing ethylenic monomer(s) to 90 to 0 mole percent (e.g. 70 to 0 mole percent) of the fluorine atom-free ethylenic monomer(s).
• the melting point or glass transition point of the fluorine-containing ethylenic polymer according to the invention can be adjusted and the polymer may be either resin-like or elastomer-like.
• the form and properties of the fluorine-containing ethylenic polymer can appropriately be selected according to the performance characteristics required of and the application field of the multilayer laminate. It is preferred, among others, that the polymer has a melting point of 150 to 270°C. Such polymer can fully show the adhesion properties of its carbonyl groups and can advantageously provide firm adhesion strength when laminated directly together with the other material.
• the melting point is more preferably not higher than 230°C, still more preferably not higher than 210°C.
• the molecular weight of the fluorine-containing ethylenic polymer to be used according to the invention is preferably within such a range that the polymer can be molded at temperatures below the heat decomposition point and that the moldings obtained can display those excellent mechanical properties, chemical resistance and other properties which are intrinsic in the fluorine-containing ethylenic polymer. More specifically, when the melt flow rate (MFR) is taken as an index of molecular weight, the MFR at an arbitrary temperature within the range of about 230 to 300°C is preferably 0.5 to 100 g/10 minutes.
• the fluorine-containing ethylenic polymer according to the invention is a fluorine-containing ethylenic polymer comprising the tetrafluoroethylene unit from the viewpoint of heat resistance and chemical resistance, or, from the viewpoint of moldability/workability, a fluorine-containing ethylenic copolymer comprising the vinylidene fluoride unit.
• fluorine-containing ethylenic polymer As preferred typical examples of the fluorine-containing ethylenic polymer according to the invention, there may be mentioned fluorine-containing ethylenic copolymers (I) to (V) whose fluorine-containing ethylenic polymer chain is a polymer chain essentially resulting from polymerization of the monomers mentioned below:
• fluorine-containing ethylenic polymers specifically mentioned above are all preferred in view of their good heat resistance, chemical resistance, weathering resistance, and electrical insulating and non-stick properties.
• copolymers (I) mentioned above there may more specifically be mentioned, for example, copolymers comprising 20 to 90 mole percent (e.g. 20 to 60 mole percent) of the tetrafluoroethylene unit, 10 to 80 mole percent (e.g. 20 to 60 mole percent) of the ethylene unit and 0 to 70 mole percent of the unit derived from a monomer copolymerizable with these.
• fluorine-containing ethylenic polymers are preferred because of their good heat resistance, chemical resistance, weathering resistance, and electrical insulating and non-stick properties, in particular.
• Preferred as the above-mentioned copolymer (II) are, for example,
• the above (II-1) to (II-3) are the perfluoro type copolymers and are most excellent in heat resistance, chemical resistance, water repellency, and non-stick, electric insulating and other properties, among fluorine-containing ethylenic polymers.
• copolymers (IV) there may be mentioned, for example, copolymers comprising 15 to 99 mole percent of the vinylidene fluoride unit, 0 to 80 mole percent of the tetrafluoroethylene unit and 0 to 30 mole percent of the unit derived from at least one of hexafluoropropylene and chlorotrifluoroethylene.
• the fluorine-containing ethylenic polymer contains a carbonyl group(s) so that its adhesiveness to the layer comprising the polyamide (A) may become more firm and strong.
• Preferred as the carbonyl group in the practice of the invention are carbonate group, carbonyl halide group and carboxyl group, which can be introduced with ease and are highly reactive with the polyamide (A).
• the number of carbonyl groups in the fluorine-containing ethylenic polymer according to the invention may appropriately be selected according to the other material to be laminated, the shape, the application field of the multilayer laminate, the adhesion strength required, the form of said polymer, etc. It is preferred, however, that the number of carbonyl groups should be 3 to 1,000, in total, per 1 ⁇ 10 6 main chain carbon atoms. When the number of carbonyl groups per 1 ⁇ 10 6 main chain carbon atoms is less than 3, a sufficient adhesion strength may not be attained. When it exceeds 1,000, the adhesion strength may be reduced as a result of chemical modification of the carbonyl groups in the step of adhesion. More preferably, the number is 3 to 500, still more preferably 10 to 300.
• the carbonyl group content in the fluorine-containing ethylenic polymer can be determined by infrared absorption spectrophotometry.
• the fluorine-containing ethylenic polymer described above When the fluorine-containing ethylenic polymer described above is heated, for instance, in the step of molding, or with the lapse of time, the carbonyl halide groups may be decomposed to form carboxylic acid. Therefore, the fluorine-containing ethylenic polymer in the multilayer laminate generally contains not only the above-mentioned carbonate groups and/or carbonyl halide groups but also carboxyl groups derived from the carbonyl halide groups when these are contained.
• R is an organic group (e.g. C 1 -C 20 alkyl group (in particular C 1 -C 10 alkyl group), an ether bond-containing C 2 -C 20 alkyl group or the like) or a group VII element].
• the carbonyl halide groups in the fluorine-containing ethylenic polymer according to the invention specifically have a structure of -COY [Y being a halogen element], and examples are -COF and -COCl.
• the fluorine-containing ethylenic polymer having such carbonyl groups itself can retain those excellent characteristics which fluorine-containing materials have, such as chemical resistance, liquid agent resistance, weathering resistance, and antifouling and non-stick properties, and can provide the molded laminate with such excellent characteristics of fluorine-containing materials without deterioration thereof.
• the mode in which the carbonyl groups are contained in the polymer chain is not particularly restricted but, for example, carbonyl groups may be bound to the polymer chain termini or side chains.
• carbonyl groups occurring at polymer chain termini are preferred since they will not markedly reduce the heat resistance, mechanical properties and chemical resistance or since they are advantageous from the viewpoint of productivity and cost.
• a method of introducing carbonyl groups into polymer chain termini using a polymerization initiator having a carbonyl group(s) or a functional group(s) convertible to a carbonyl group(s), for example a peroxy carbonate or peroxy ester is preferred embodiment since introduction can be realized very easily and the content of carbonyl groups introduced can be controlled with ease.
• the carbonyl group derived from a peroxide so referred to herein means a carbonyl group directly or indirectly derived from a functional group contained in a peroxide.
• the production method of the fluorine-containing ethylenic polymer according to the invention is not particularly restricted but may comprise subjecting the monomer or monomers corresponding to the desired fluorine-containing polymer in species and mixing ratio to radical polymerization or ionic polymerization.
• the technique of suspension polymerization in an aqueous medium using a fluorine-containing solvent and, as polymerization initiator, a peroxy carbonate or the like is preferred from the industrial viewpoint.
• a fluorine-containing solvent may be used in addition to water.
• hydrochlorofluoroalkanes e.g.
• the fluorine-containing solvent is preferably used in an amount of 10 to 100% by weight relative to water.
• the polymerization temperature is not particularly restricted but may be 0 to 100°C.
• the polymerization pressure is to be selected according to the species, amount and vapor pressure of the solvent employed, the polymerization temperature and other polymerization conditions. Generally, it may be 0 to 9.8 MPaG.
• chain transfer agents for example hydrocarbons such as isopentane, n-pentane, n-hexane and cyclohexane; alcohols such as methanol and ethanol; and halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride and methyl chloride.
• hydrocarbons such as isopentane, n-pentane, n-hexane and cyclohexane
• alcohols such as methanol and ethanol
• halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride and methyl chloride.
• fluorine-containing ethylenic polymer having the carbonyl group there may be mentioned the method comprising subjecting a carbonyl group-containing monomer to copolymerization.
• carbonyl group-containing ethylenic monomer there may be mentioned fluorine-containing monomers such as perfluoroacryloyl fluoride, 1-fluoroacryloyl fluoride, acryloyl fluoride, 1-trifluoromethacryloyl fluoride and perfluorobutenoic acid and fluorine-free monomers such as acrylic acid, methacrylic acid, acryloyl chloride and vinylene carbonate.
• the polymer may also be obtained by subjecting a fluorine-containing ethylenic polymer, a grafting compound having a carbonyl group-containing functional group, and a radical generator such as a peroxide to grafting under melting and mixing at a temperature at which radical generation occurs in the extruder.
• the method comprising using a peroxide, in particular a peroxy carbonate or a peroxy ester, as the polymerization initiator can preferably be employed from the economical viewpoint and the quality viewpoint, for example heat resistance and chemical resistance.
• a peroxide in particular a peroxy carbonate or a peroxy ester
• the polymerization initiator can preferably be employed from the economical viewpoint and the quality viewpoint, for example heat resistance and chemical resistance.
• this method it is possible to introduce, into a polymer chain terminus or termini, carbonyl groups derived from a peroxide, for example carbonate groups derived from a peroxy carbonate, ester groups derived from a peroxy ester, or carbonyl halide groups derived therefrom by functional group conversion.
• peroxy carbonates can lower the polymerization temperature without involvement of side reactions in the initiation reaction, hence are preferably used.
• R and R' each represents a straight or branched, saturated univalent hydrocarbon group having 1 to 15 carbon atoms or an alkoxy group-terminated, straight or branched, saturated univalent hydrocarbon group having 1 to 15 carbon atoms and R" represents a straight or branched, saturated divalent hydrocarbon group having 1 to 15 carbon atoms or an alkoxy group-terminated straight or branched, saturated divalent hydrocarbon group having 1 to 15 carbon atoms.
• diisopropyl peroxydicarbonate di-n-propyl peroxydicarbonate
• tert-butylperoxy isopropyl carbonate bis(4-tert-butylcyclohexyl) peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate and the like.
• the amount of the initiator to be used may vary depending on the desired polymer species (e.g. composition), molecular weight, polymerization conditions and the initiator species employed. Generally, however, it is preferably 0.05 to 20 parts by weight, in particular 0.1 to 10 parts by weight, per 100 parts of the polymer to be obtained by the polymerization.
• the terminal carbonate group or ester group content can be controlled not only by the use of such a polymerization initiator as a peroxy carbonate or peroxy ester but also by adjusting the polymerization conditions such as the amount of the chain transfer agent used and the polymerization temperature.
• fluorine-containing ethylenic polymers having a carbonyl halide group or groups at a polymer molecule terminus or termini can be obtained by heating, for causing thermal decomposition (decarboxylation) of the above-mentioned fluorine-containing ethylenic polymers having carbonate group(s) or ester group(s) at a terminus or termini, as mentioned above.
• the heating temperature depends on the carbonate group or ester group species and the fluorine-containing ethylenic polymer species.
• heating is made so that the temperature of the polymer itself may reach 270°C or above, preferably 280°C or above, most preferably 300°C or above.
• the upper limit to the heating temperature is preferably not higher than the thermal decomposition temperature of other sites than the carbonate group or ester group of the fluorine-containing ethylenic polymer and, more specifically, not higher than 400°C, more preferably not higher than 350°C.
• the fluorine-containing ethylenic polymer according to the invention is preferably used alone so that the adhesiveness, heat resistance and chemical resistance, intrinsic in itself may not be impaired.
• various fillers such as inorganic powders, glass fiber, carbon fiber, metal oxides and carbon may be incorporated therein at levels which will not deteriorate the performance characteristics thereof.
• pigments, ultraviolet absorbers and other optional additives may be formulated.
• a resin for example another fluororesin or a thermoplastic or thermosetting resin, a synthetic rubber or the like to thereby improve the mechanical properties and weathering resistance, provide decorativeness, prevent electrostatic charging, improve the moldability, and so on.
• an electrically conductive material such as carbon black or acetylene black, is of advantage in preventing electrostatic charge accumulation on such products as tubes and hoses in fuel piping systems, hence is preferred.
• the layer comprising the fluorine-containing ethylenic polymer (B) comprises the above-described fluorine-containing ethylenic polymer and another or other components incorporated according to need and, where necessary, the layer comprising the above fluorine-containing ethylenic polymer (B) may be electrically conductive.
• electrically conductive means that while electrostatic charge may accumulate upon continuous soaking of an insulating material such as a resin with an inflammable fluid such as gasoline, whereby the possibility of inflammation arises, the layer has an electrical property such that this electrostatic charge accumulation will not occur. It is provided in SAE J2260, for instance, that the surface resistivity should be not higher than 10 6 ⁇ / ⁇ .
• the above-described electrically conductive material is incorporated preferably at a level not more than 20% by weight, more preferably not more than 15% by weight, in the composition constituting the above layer.
• the lower limit is such a level that can provide the surface resistivity described above.
• the layer comprising the above fluorine-containing ethylenic polymer (B) may be further laminated to a layer (C) comprising a fluorine-containing resin.
• the above layer (C) comprising the fluorine-containing resin may contain an electrically conductive material for providing the laminate with electric conductivity.
• the level of addition of the electrically conductive material may be such that electric conductivity can be provided.
• the addition level may be as described above.
• the above fluorine-containing resin is not particularly restricted but may be any melt-moldable fluorine-containing resin, including, for example, tetrafluoroethylene/fluoro(alkylvinyl ether) copolymers (PFA), tetrafluoroethylene/hexafluoropropylene copolymers (FEP), ethylene/tetrafluoroethylene copolymers (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene/chlorotrifluoroethylene copolymers (ECTFE), polyvinyl fluoride (PVF) and polyvinylidene fluoride (PVDF). It may be the above-described fluorine-containing ethylenic polymer.
• the above fluorine-containing resin may have a melting point not lower than 260°C.
• those having a melt flow rate of 0.5 to 100 g/10 minutes at an arbitrarily selected temperature between 230°C and 300°C are suited for use in producing multilayer laminates such as fuel piping tubes and hoses, etc., which retain a low level of liquid agent/fuel permeability and are excellent in flexibility, cold temperature impact resistance, heat resistance and so forth, by simultaneous multilayer coextrusion with the polyamide.
• a special feature of the present invention is that a fluorine-containing resin having a relatively high melting point, namely a melting point of not lower than 250°C, can be used as the above-mentioned fluorine-containing resin. While, among the conditions of extruding fluorine-containing resins, including the above-described fluorine-containing ethylenic polymer (B), the die temperature alone is restricted, the melt flow in the die section can be secured by setting the cylinder temperature at a sufficiently high level, so that multilayer laminates having such a constitution can easily be produced by simultaneous multilayer coextrusion.
• Fluorine-containing resins having a high melting point are excellent in chemical resistance and have low level of liquid agent permeability in proportion to the melting point and can be used with great advantage, in particular, in those fields in which a high level of liquid agent impermeability is required, for example, for automotive fuel piping.
• the fluorine-containing resin of the above (B) and the resin in the above layer (C) may be the same or different.
• the present invention is also applicable to the production of multilayer laminates in which the layer comprising the above (B) is further laminated with a layer (A') comprising a polyamide in lieu of the layer (C) comprising the fluorine-containing resin.
• the layer (A') comprising the polyamide may contain an electrically conductive material for providing electric conductivity.
• the polyamide may be the same as or different from the above (A).
• the present invention is further applicable to the production method of multilayer laminates in which the layer (C) comprising a fluorine-containing resin and not containing the electrically conductive material is further laminated with a layer (D) comprising a fluorine-containing resin and containing an electrically conductive material.
• the level of addition of the electrically conductive material may be such that electric conductivity can be provided.
• the addition level may be as mentioned above.
• Any of the fluorine-containing resins mentioned above may be used as the fluorine-containing resin constituting the layer (D), and the fluorine-containing resin may be the same as or different from the resin in the above layer (C), and it may have a melting point of not lower than 250°C.
• the production method according to the present invention comprises laminating at least the above-described (A) and (B), where necessary together with the other layer(s) described above, one over the other in a adhered state using the above-described coextruding apparatus.
• the line speed of the laminate may be, for example, 4 to 20 m/minute. It is also possible to produce lined products by laminating the multilayer laminate molded by the production method of the invention with another substrate.
• the draw down ratio as expressed in terms of the ratio of the die opening area to the sectional area of the molded article actually obtained, is not particularly restricted.
• the draw ratio balance is preferably around 1.
• the above heat treatment is carried out at 60°C or above, more preferably at 80°C or above.
• the multilayer laminate obtained by the production method of the present invention can have an initial interlayer adhesion strength between the layer comprising the polyamide (A) and the layer comprising the fluorine-containing ethylenic polymer (B) of not less than 30 N/cm or, further, not less than 40 N/cm, as shown later herein in the example section.
• an initial interlayer adhesion strength between the layer comprising the polyamide (A) and the layer comprising the fluorine-containing ethylenic polymer (B) of not less than 30 N/cm or, further, not less than 40 N/cm, as shown later herein in the example section.
• the layer comprising the fluorine-containing ethylenic polymer (B) may have a thickness less than 0.5 mm.
• the layer comprising the above (B) may be thin.
• the layer comprising the above (B) may be less than 1.5 times the thickness of the layer (C) or, in case that the layer (D) is further laminated, less than 1.5 times the total thickness of the layer (C) and layer (D).
• the layer comprising the above (B) is to serve as an intermediate adhesive layer, it is therefore possible to reduce the thickness of the adhesive layer. This is economically advantageous.
• the production method of the invention can appropriately be applied to the production of such multilayer laminates as listed below, for example:
• preferred embodiments are, for example, as follows:
• the multilayer laminate may have a jacket layer as the outermost layer thereof for the purpose of protection, antifouling, insulation and/or shock absorbance, etc.
• the jacket layer can appropriately be formed by the simultaneous coextrusion using a resin or a natural or synthetic rubber, for instance, or in a separate step of covering. It is also possible to reinforce the laminate with a metal or the like.
• the multilayer laminate obtainable by the production method of the invention is excellent in low level of permeability particularly against liquid agents, namely such liquid agents capable of deteriorating polyamide resins as solvents or fuels, for example; organic acids such as acetic acid, formic acid, cresol and phenol; inorganic acids such as hydrochloric acid, nitric acid and sulfuric acid; solutions of alkalis such as sodium hydroxide and potassium hydroxide; alcohols such as methanol and ethanol; amines such as ethylenediamine, diethylenetriamine and ethanolamines; amides such as dimethylacetamide; esters such as ethyl acetate and butyl acetate; fuels such as gasoline, light oil and heavy oil, pseudofuels such as Fuel C, and mixed fuels composed of these and a peroxide, methanol, ethanol or the like; and other organic and inorganic liquids.
• liquid agents namely such liquid agents capable of deteriorating polyamide resins as solvents or fuels, for example;
• Infrared absorption spectrometric analysis was carried out using a Perkin-Elmer FTIR spectrometer 1760X (product of Perkin-Elmer) by performing scanning 40 times.
• the baseline of the IR spectrum obtained was automatically determined using a Perkin-Elmer Spectrum for Windows Ver. 1.4C, and the absorbance of the peak at 1809 cm -1 was measured.
• the film thickness was measured using a micrometer.
• the temperature was raised at a rate of 10°C/min and the melting peaks were recorded.
• the temperature corresponding to the maximum value was reported as the melting point (Tm).
• the weights (g) of the polymer flowing out through a nozzle with a diameter of 2 mm and a length of 8 mm within a unit time (10 minutes) were measured under a load of 5 kg at different temperatures.
• Test specimens with a width of 1 cm were cut from each tube and subjected to 180° peel testing at a rate of 25 mm/min on a Tensilon universal tester. The mean of five maximum values found on an elongation-tensile strength graph was reported as the interlayer adhesion strength.
• the method used was as described in SAE J 2260.
• the result was expressed in terms of the number of tube specimens, out of 10, showing, in the burst test after the falling ball test, a burst pressure of not more than 75% of that before the falling ball test.
• the result "0/10" indicates that all the tubes tested after the falling ball test showed a burst pressure exceeding 75% of that before the falling ball test.
• polyamides and fluorine-containing ethylenic polymers used in the following examples were as follows:
• An autoclave was charged with 380 L of distilled water and, after thorough nitrogen purging, charged with 75 kg of 1-fluoro-1,1-dichloroethane, 155 kg of hexafluoropropylene and 0.5 kg of perfluoro(1,1,5-trihydro-1-pentene), and the system inside was maintained at 35°C and at a stirring rate of 200 rpm. Thereafter, tetrafluoroethylene was charged under pressure to 0.7 MPa, followed by charging of ethylene under pressure to 1.0 MPa. Then, 2.4 kg of di-n-propyl peroxydicarbonate was charged to initiate the polymerization.
• Fluorine-containing ethylenic polymers F-B and F-C were produced in the same manner as in Synthesis Example 1. The results of analysis of these are shown in Table 1.
• An autoclave was charged with 400 L of distilled water and, after thorough nitrogen purging, charged with 320 kg of perfluorocyclobutane, 80 kg of hexafluoropropylene, 19 kg of tetrafluoroethylene and 6 kg of vinylidene fluoride, and the system inside was maintained at 35°C and at a stirring rate of 180 rpm. Thereafter, 5 kg of di-n-propyl peroxydicarbonate was charged to initiate the polymerization.
• An autoclave was charged with 400 L of distilled water and, after thorough nitrogen purging, charged with 75 kg of 1-fluoro-1,1-dichloroethane, 190 kg of hexafluoropropylene and 1.5 kg of perfluoro(1,1,5-trihydro-1-pentene), and the system inside was maintained at 35°C and at a stirring rate of 200 rpm. Thereafter, tetrafluoroethylene was charged under pressure to 0.7 MPa, followed by charging of ethylene under pressure to 1.0 MPa. Then, 2.6 kg of di-n-propyl peroxydicarbonate was charged to initiate the polymerization.
• the fluorine-containing ethylenic polymer F-B obtained in Synthesis Example 2 was dry-blended with an electrically conductive material (acetylene black) in a mixing ratio of 85/15 by weight, and the mixture was melted and kneaded in the same manner as in Synthesis Example 5 except that the cylinder temperature was 245°C.
• the results of analyses of the thus-obtained pellets (fluorine-containing ethylenic polymer F-F) are shown in Table 1.
• TFE stands for tetrafluoroethylene
• Et for ethylene
• HFP for hexafluoropropylene
• VdF vinylidene fluoride
• HF-Pe perfluoro(1,1,5-trihydro-1-pentene).
• a tube with an inside diameter of 6 mm and an outside diameter of 8 mm was molded continuously by feeding the polyamide PA-A, the fluorine-containing ethylenic polymer F-A and the commercially available electric conductive fluororesin F-J so that they might form the outer layer, intermediate layer and inner layer, respectively.
• the size of the die mandrel was 12 mm/16 mm.
• the molding conditions and the results of evaluation of the tube obtained are shown in Table 2.
• the flat portion of the die mandrel had a length of 50 mm (in the table, referred to as "die length").
• Multilayer tubes were molded in the same manner as in Example 1 except that the tube line speed was changed.
• the molding conditions and the results of evaluation of the tubes obtained are shown in Table 2.
• Multilayer tubes were molded in the same manner as in Example 1 except that the fluorine-containing ethylenic polymer for forming the intermediate layer was changed and the cylinder temperature was changed according to that material (Examples 4 to 6 and Comparative Example 1). Further, a multilayer tube was molded in the same manner as in Example 1 except that the die temperature was lowered (Comparative Example 2). The molding conditions and the results of evaluation of the tubes obtained are shown in Table 2 (Examples 4 to 6) and Table 3 (Comparative Examples 1 and 2).
• a multilayer tube was molded in the same manner as in Example 1 except that F-I was used as the fluorine-containing ethylenic polymer for forming the inner layer and the cylinder temperature was changed accordingly.
• the molding conditions and the results of evaluation of the tube obtained are shown in Table 2.
• Table 2 indicate, firm adhesion, like in the case of the use of the conductive fluororesin, was attained even when the non-conductive fluororesin F-1 was used for forming the inner layer.
• tubes with an inside diameter of 6 mm and an outside diameter of 8 mm were molded continuously by feeding the polyamide resin PA-A, the fluorine-containing ethylenic polymer F-A, the fluororesin F-I (Example 8) or F-H (Example 9) and the conductive fluororesin F-J so that they might form the outer layer, intermediate layer, inner layer and innermost layer, respectively.
• the molding conditions and the results of evaluation of the tubes obtained are shown in Table 2. As the results shown in Table 2 indicate, sufficiently high adhesion strength was obtained even when the inner layer was composed of two layers.
• the ETFE having a high melting point excellent in fuel impermeability could be extrusion-molded (Example 9) as well.
• tubes with an inside diameter of 6 mm and an outside diameter of 8 mm were molded continuously by feeding the polyamide resin PA-A and the fluorine-containing ethylenic polymers so that they might form the outer layer and inner layer, respectively.
• the molding conditions and the results of evaluation of the tubes obtained are shown in Table 2 (Examples 10 to 13) and Table 3 (Comparative Examples 3 to 5).
• Table 2 Examples 10 to 13
• Table 3 Comparative Examples 3 to 5
• Multilayer tubes were molded in the same manner as in Example 1 except that the outer layer-forming polyamide was changed.
• the molding conditions and evaluation results are shown in Table 3. As the results shown in the table indicate, sufficiently high levels of adhesion strength could be obtained, even when the plasticizer-containing polyamides were used in lieu of the plasticizer-free ones. On the other hand, when the die temperature was low, no sufficient adhesion strength could be obtained even when the fluorine-containing ethylenic polymer F-A or F-B was used as the intermediate layer, as indicated by the results in the comparative examples.
• a multilayer tube was molded in the same manner as in Example 14 except that the line speed was set at 20 m/minute and the mandrel size was changed to 18 mm/24 mm.
• the molding conditions and evaluation results are shown in Table 3. From the table, it is seen that sufficiently firm adhesion could be obtained even when the draw down ratio was increased.
• a multilayer tube was molded in the same manner as in Example 2 except that the length of the flat section of the die mandrel was 200 mm.
• the molding conditions and evaluation results are shown in Table 3. From the table, it is seen that a sufficient adhesion strength could be obtained even when the length of the flat portion was increased.
• Example Comparative Example 18 8 9 Outer layer resin PA-D PA-D PA-D Inner layer resin F-A F-A F-A Cylinder temp.
• the present invention which has the constitution described above, can markedly improve the interlayer adhesion strength of multilayer laminates, in particular the interlayer adhesion strength between a polyamide and a fluorine-containing ethylenic polymer, as compared with the prior art production methods in a simple and easy manner. Furthermore, the adhesion strength of the multilayer laminate as a whole can be markedly improved by using a fluorine-containing ethylenic polymer having carbonyl groups, without requiring any additional step, and a multilayer laminate excellent in cold temperature impact resistance can be produced by simultaneous multilayer coextrusion using a commercially available polyamide.
• the molding can be provided with good mechanical properties and high-level durability in an external environment, for example against heat and various chemical substances, by disposing such a polyamide as an outer layer and, in addition, a multilayer laminate can economically be produced by disposing a fluorine-containing resin layer as the innermost layer to thereby provide the molding with those heat resistance, oil resistance, chemical resistance and low level of liquid agent permeability which the fluorine-containing resin has. This is very advantageous from the industrial point of view.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Laminated Bodies (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)

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• 2001
  • 2001-03-23 US US10/239,244 patent/US7132073B2/en not_active Expired - Lifetime
  • 2001-03-23 DE DE60140116T patent/DE60140116D1/de not_active Expired - Lifetime
  • 2001-03-23 KR KR1020027012363A patent/KR100830789B1/ko not_active Expired - Lifetime
  • 2001-03-23 WO PCT/JP2001/002366 patent/WO2001070485A1/fr not_active Ceased
  • 2001-03-23 EP EP01915745A patent/EP1283101B1/fr not_active Expired - Lifetime
  • 2001-03-23 JP JP2001568719A patent/JP4096556B2/ja not_active Expired - Fee Related

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